Statistical modelling/Numbers of cattle

The variance components show that there was no significant variation among sub-regions, but there was some indication of differences between dip tank areas within sub-regions.

It should be noted, however, that we are making an assumption that the dip tank areas were selected at random, when in fact their selection was not strictly random; purposive sampling was involved in some cases as indicated under Study design.



**** REML Variance Components Analysis *****

Response Variate : log_cat_no
 

*** Estimated Variance Components ***

Random term   Component

S.e.

subregion   0.0154

0.0173

subregion.diptank  0.0341

0.0198


*** Residual variance model ***
Term  Factor  Model Parameter 

Estimate

S.e.

Residual      Identity Sigma2

0.442

0.0341


*** Wald tests for fixed effects ***
Fixed term  Wald statistic  d.f.  Wald/d.f.  Chi-sq prob
livst_inc2  6.03   1 6.03  0.014